The present invention relates to the field of electrolysis cells or installations. FIG. 1 is a diagram of an electrolysis installation 100 used for producing fluorine. The installation 100 comprises a tank 101 containing an electrolyte 102, e.g. a solution of hydrofluoric acid (HF), and having two series of electrodes immersed therein, namely a first series of cathodes 103 and a second series of anodes 104. The anodes 104 are fastened and electrically connected to each side of a busbar 105. The busbar 105 serves both as a support and as a distributor of electrolysis current for the electrodes 104. In well-known manner, the busbar 105 is connected to the positive terminal of a direct current (DC) generator (not shown in the figures) by conductors 106 placed in threaded rods 107, while the cathodes 103 are connected to the negative terminal of the generator. The anodes 104 are distributed longitudinally on each side of the busbar 105 and they project beyond the bottom face 105a of the busbar.
FIG. 2 shows the electrolysis installation 100 while it is in operation, i.e. when the electrodes 103, 104 are immersed in the electrolyte and are powered by the DC generator. When the electrolyte is made up of hydrofluoric acid, for example, electrolysis leads to bubbles of gaseous fluorine 108 being given off at the anodes 104 and bubbles of hydrogen 109 being given off at the cathodes 103. The bubbles of these two gaseous species rise to the surface of the electrolyte and they are collected by independent ducts (not shown in the figure) in the top portion of the electrolysis installation 100.
The bubbles of gaseous fluorine 108 give rise to corrosion and erosion of the elements of the installation with which they come into contact during electrolysis. Given their chemical nature, the bubbles 108 are very corrosive, and as they rise towards the surface of the electrolytes they give rise to an erosion phenomenon on the anodes 104 and more particularly on the busbar 105 whose bottom face 105a receives practically all of the fluorine bubbles given off by the inside walls of the anodes 104, these bubbles then flowing along the bottom face 105a until they find a path to the surface of the electrolyte 102.
Consequently, in any electrolysis installation that produces one or more corrosive gaseous species, the corrosion and the erosion resulting from the gases being given off make it necessary to replace the busbar and the anodes frequently.
To mitigate this problem, one solution consists in making the busbar and possibly also the anodes out of graphite, which is a material that is known to present good resistance to corrosion. Nevertheless, even though graphite does present improved resistance to the combined corrosion and erosion phenomenon compared with the metal materials commonly used, that is not sufficient to prevent the anodes and above all the busbar deteriorating during electrolysis. Thus, even when made of graphite, busbars need to be replaced frequently. On each replacement, the electrolysis installation, and consequently the production of the gaseous species, must be stopped. Busbar wear by the corrosion-erosion phenomenon thus leads to periods in which the electrolysis installation is not in operation and it is desirable for these periods to be shortened in order to improve the efficiency of the installation.